Machine for manufacturing brake drums



MACHINE FOR MANUFACTURING BRAKE DRUMS Filed NOV. 20. 1929 2ShSGtEv-Shfi'i 1 3s .z7-- v 40 43 l I 13 38 24V: 2a E] 22 B INVENTOR.

ATTORNEY.

Aug. 23, 1932. H. FORD MACHINE FOR MANUFACTURING BRAKE DRUMS- Filed Nov.20. 1929 2 Sheets-Sheet 2 INVENTOR.

A TTORNE Y.

Patented Aug. 23, 1932 UNITED STATES PATENT oFF ca' HENRY FORD, 0FDEARBORN, MICHIGAN, ASSIGNOB TO FORD MOTOR COJ IPANY, 01'

DEAR-BORN, MICHIGAN, -A CORPORATION OF DELAWARE MACHINE FORMANUFACTURING BRAKE DRUMS Application filed November 20, 1929. SerialNo. 408,838.

The object of my invention is to provide a brake drum of simple, durableand inexpensive construction.

A further object of my invention is to provide a brake drum having abraking surface superior to the ground surface ordinarily provided onbrake drums.

Still a further object of my invention is to provide a machine for usein the manufacture of such drums, the purpose of the machine being toproduce the superior braking surface by a rolling process instead of bygrinding.

The conventional method of manufacturing brake drums consists in cuttinga suitable blank from flat steel stock, then drawing the blank in apunch press to the shape of the drum, and then grinding the brakingsurface of the drum in a conventional grinding machine. The sheet steelused in the manufacture of brakeldrums varies slightly in thickness dueto the rolling mill operations so that if the braking surface of thedrum were not rendered smooth this uneven surface would soon destroy thebrake lining. Further, the surface of such sheets of steel have smallpieces of scale attached thereto which tend to unnecessarily wear downthe'brake lining if not removed or rendered smooth. v

\Vhen the drums come from the punch press dies they are not trulycircular due to variations in these dies. These Variations areunavoidable due to the enormous strain of the drawing operations so thatthe braking surface must be made round by a subsequent 4,0 of a roughgrind and a finish grind.

operation. Grinding has universally been used for smoothing the brakingsurface and making the drum truly circular.

The customary grinding operations consist These operations remove thescale from the steel and produce a braking surface which is trulycircular. Further the braking surface is smooth so that the life of thebrake lining is materially increased. One disadvantage to these grindingoperations is that their cost adds materially to the total cost of thedrum.

The brake drum, is considerably cheaper to manufacture than theconventional brake drum because no about to be described,

grindin operations are required thereon.

The bra 'ng surface of the drum instead of being ground is rolled, asfurther described in the specification, so that a truly circular brakingsurface results and one that is much smoother than the ground surface inthe ordinary brake drum. Further, this rollin o eration may compact themetal of the ra ing surface so that a drum having a longer life results.Microscopic examination has shown that the surface produced by thisrolling operation is much smoother than the commerciall; ground surface,The pores in the steel are closed and there are of course no emeryparticles imbedded in the surface to detract from its smoothness orcause excessive wear on the lining used with the surface.

Still a further object of my invention is to provide a machine having aplurality of' rollers therein andvto provide bearings for guiding theserollers in the brake drum. A

novel feature of this machine is the method of operating these rollersso that the rollin strain is not taken through the bearings used toguide the rollers. Heretofore, when it has been desired to roll thesurface of a piece of metal, such as in a knurling operation, the

'knurling roller has been rotatably mounted in a pair of bearings. Thesebearings are subject to the full strain produced by the knurlingoperation sothat they frequently need to be renewed. If such a methodwere used by the applicant to hold his rollers it would be almostimpossible to obtain consistently accurate results, and it is due to theimproved rolling device described herein that such accurate results areobtained. The bearings used with the applicants rollers function solelyto guide the rollers. They do not support the rollers against thebraking surface and are thus not subject to the rolling strain. Therollers are mounted at a slight angle to the rotating axis of themachine so that the device may be self-feeding.

With these and other objects in view my invention consists in theconstruction, combination, and arrangement, of the various parts of myimproved device, as described in the specifications, claimed in myclaims, and

illustrated in the accompanying drawings,

in which: p

Figure 1 shows a side elevation of my 1mproved rolling machine. 8

- Figure 2 shows a central, vertical sectional, view through the rollingfixture s own F 're 3 illustrates the method of mounting e rollers so asto obtain a self-feeding device.

Referrin to the accompanying drawings, I have used the reference numeral10 to indicate generally'a brake drum for use with a motor vehicle. Thisdrum consists of a radially extending web 11 having an annular sleeve12'formed integral therewith and tical adjustment on the'forward facethereof by means of a screw 16. 'A spindle 17 is rotatably mounted in asleeve 18, this sleeve being reciprocally mounted in the upper'part I gof the frame 14. An electric motor 19 is arranged to rotate the spindle17 through suitcular portion 23 over the outer edgeof which able gearing20 while the sleeve 18 and s indle 17 maybe reciprocated by means of aandwheel 21.

The structure just described merely illustrates one of the many ways inwhlch my improved brake drum rolling fixture ma be operated, and I donot wish to limit the manufacture of my improved brake drum to thisparticular type of machine. a

Referring to Figure 2, a base plate22 is fastened on the table 15. Thisbase plate is provided with an upwardly extending cira ring-'24isfloatingly mounted,.there being sufliclent clearance between-these twomembers to allow a slight radial movement there: between. The portion 23is provided 'with a plurality of radially extending openings 25separated.

7 into which springs 26 and spring seats 27 are mounted. A plurality oflugs 28 are secured to the lower edge of the r1ng24 by means'of suitablescrews sothat the late 22 and the ring 1 24 may not be acci entally Ifit were not for the springs 26 and the spring seats 27 acting againstthe inner surface of the ring 24, the ring would be free to rotaterelative to the plate .22. However, these springs exert suflicientpressure so that i 5 the ring 24 is frictionally held by the seats 27from rotation relative to the plate 22. The

ring is substantially free to move a short distance radially on the late22.

The upper portion 0 the ring 24 forms a die for receiving the brake drum10. The

opening in this portion of the ring is of truly clrcular shape, and themetal of the ring is of suflicient hardness so the action. of therollers which will later be described will not deform this opening. Forclearness this die face or opening has been given the numeral 29. j

Several radially extending openings 48 are provided in the ring .24 anda ball 30 and spring 31 are secured in each of these openings by a screw32. Y

A brake drum 10 is inserted web down.- wardly into the die 29 of thering24. The web portion 11 of the brake drum 1s provided with a squaredopenin 33 which co-acts with :a similarly squared plot 34 which issecured to the plate 22 by means of screws 35. The pilot 34 enters thesquared o ening33 in the web 11 so that the brake rum may be resistedfrom turning relative to the plate 22.

Considerable pressure is necessary to force the alrum into this opening29 against the urging-of the balls 30 and springs 31. However, thesemembers serve to keep the drum from accidentally being Withdrawn fromthe die opening during the rolling operation.

The lower end of the spindle 17 is pro vided with a conventional taperedopening I adapted to receive a tapered shank 36. A flange 37 extendsradially from the lower end of the shank 36 and. a ring-shaped driver 38is secured to this flange by means of screws 39. The member 38 ishardened and ground to a true circle.

.A roller retaining member 49 is rotatably y mounted on the shank 36above the flange 37 and is restrained from axial movement thereto bymeans of nuts 40. This retaining member 49 is provided with a pluralityof bearings 41 drilled therein describing a circular locus somewhatlarger than the driver 38. A bearing stem 42 is rotatably mounted ineach of these bearings and rollers 43 formed integral with the stems 42extend downwardly adjacent to the outer edge of the driver 38. Anannular groove 44 is formed in the'upper end of each stem 42 whichco-acts with 9. lug 45 secured to the upper face of the retaining member49 by screws 46, to thereby prevent axial displacement of the rollers43. It will be noted that there is no positive driv- "ing connectionbetween the shank 36 and the retaining member 49 or rollers 43.

' Referring to Figure 3 means are shown for feeding the device. Thebearings 41 are drilled at a slight angle 50, approximately into thebrake drum so that little or no exertion-is required to feed the device.

For producing my improved brake drum, a blank is drawn in a punch pressto a size slightly smaller than the finished size of the drum, and isthen inserted in the die 29. The driver 38 is then rotated in thedirection shown by the arrow 47 and the handwheel' to a true circlecorresponding to the die 29.

Among the many advantages arising from the use of my improved device, itmay be well to mention that an extremely smooth and perfectly roundbraking surface is obtained which in many respects is superior to aground surface. Further, the floating die incorporated in this deviceeliminates the necessity for an extremely accurate setting of the dies.Still further, the rollers being driven by a master driver, do not exertthe rolling pressure on the bearings 41 so that the life of the machineis prolonged.

Some changes may be made in the arrangement, construction, andcombination, of the various parts of my improved device withoutdeparting from the spirit of my invention and it is my intention tocover b my claims such chan es as may reasonably be includedwithin t escope thereof.

I claim as my invention:

1. In a machine for rolling the braking surface of brake drums, a baseplate, a die resiliently mounted upon said base plate adapted to receivesaid drum, a driver rotat ably driven within'said drum, and a plu ralityof rollers disposed between said driver and drum for the purposedescribed.

2. In a device for smoothing and truing the cylindrical walls of a sheetmetal brake drum, a cylindrical die adapted to loosely receive saiddrum, a non-circular shaped pilot associated with said die coacting witha correspondingly shaped opening in said drum preventing relativerotation between the die and drum, and rollers adapted to rotate aroundthe inside of said drum to thereby squeeze the material of the drumagainst the die and eircumferentially expand the drum to intimately fitsaid die.

8. In a device for smoothing and truing the cylindrical walls of a sheetmetal brake drum, a rigid die having a truly cylindrical brake drumreceiving opening therein materially larger than said drum, and anoncircular'pilot associated with said die coacting with acorrespondingly shaped opening in said drum preventing relative rotationbetween the die and drum, and a roller adapted to progressively squeezeeach portion of the drum against the die thereby circ'umferentiallyexpanding the drum to intimately fit said die.

4. In a device for smoothing and truing the walls of a flexible metalcylinder, at cylindrical die adapted to looselyreceive said cylinder,means associated with said die for preventing relative rotation betweenthe die and cylinder, a cylindrical driver adapted to be rotated withinsaid die, a roller retaining 7 member rotatably mounted upon saiddriver,

and a plurality of rollers rotatably mounted in said retainer torollbetween saiddriver and the cylindrical membcr, the driver and rollersand die being so proportioned that the metal of'said member is expandedcircumferentially into intimate contact with said die;

5. In a device for smoothing and truing the cylindrical walls of a sheetmetal brake drum, a rigid die having a cylindrical drum receivingopening therein adapted to loosely receive said drum, means associatedwith said die for preventing relative rotation between the die and drum,a cylindrical driver adapted to be rotated within said die, a rollerretaining member rotatably mounted upon said driver, and a pluralityofrollers rotatably mounted in said retainer to roll between the driverand brake drum, said'rollers progressively squeezing the individualportions of the drum against the die so as to circumferentially expandthe drum into intimate contact with said die.

.6. In a device for smoothing and truing the cylindrical walls of asheet 'metal brake drum, a rigid die having a truly cylindrical brakedrum receiving opening therein materially lar r than said drum, a pilotassociated witi said die preventing relative rota-, tion between saiddie and the drum, a cylindrical driver adapted to be rotated within saiddie, a roller retaining member rotatably mounted relative to said driverand die, and

a plurality of rollers rotatably mounted in said retainer to rollbetween the driver and brake drum, said rollers progressivel squeezingthe individual portions of t e drum against the die so as tocircumferentially ex-' pand the drum into intimate contact with saiddie.

7. In a device for smoothing and truing the cylindrical walls of a sheetmetal brake drum, a rigid die having a cylindrical drum receiving openintherein materially larger than said brake rum, a non-circular shapedpilot associated with said die coacting with a correspondingly shapedopening in said drum preventing relative rotation between the die anddrum, a cylindrical driver adapted to be rotated within the die anddrum, a roller retaining member rotatably mounted within said die and onsaid driver, and a plurality of rollers rotatably mounted in saidretainer to roll between the driver and brake drum,

I said rollers progressively squeezing the individual portions of thedrum against the die so as to circumferentially expand the drum intointimate contact with said die.

8. In a device for smoothing and truing the cylindrical 'walls of asheet metal brake drum, a rigid die having a cylindrical drum receivingopening therein materially larger than said drum, a square pilotassociated with said die projecting through a squared opening in the webof said drum whereby relative rotation between the die and drum isprevented,

.a c lindrical driver adapted to be rotated wit in said die, a rollerretaining member rotatably mounted upon said driver, and a plurality ofrollers rotatably mounted in said retainer to roll between the driverand brake drum, said rollers progressively squeezing the individualportions of the drum against the die so as to circumferentially ex andthe drum into inimate contact with said ie.

; HENRY FORD.

